[RFC PATCH 1/2] bdi: Create a flag to indicate that a backing device needs stable page writes
flat view
STALE5096d
From: Darrick J. Wong <hidden>
Date: 2012-10-27 01:36:52
Also in:
linux-fsdevel
Subsystem:
block layer, memory management, memory management - misc, the rest · Maintainers:
Jens Axboe, Andrew Morton, David Hildenbrand, Linus Torvalds
This creates BDI_CAP_STABLE_WRITES, which indicates that a device requires stable page writes. It also plumbs in a sysfs attribute so that admins can check the device status. Signed-off-by: Darrick J. Wong <redacted> --- block/blk-integrity.c | 8 ++++++++ include/linux/backing-dev.h | 6 ++++++ mm/backing-dev.c | 11 +++++++++++ 3 files changed, 25 insertions(+)
diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index da2a818..d05d7b3 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c@@ -384,6 +384,7 @@ EXPORT_SYMBOL(blk_integrity_is_initialized); int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template) { struct blk_integrity *bi; + struct backing_dev_info *bdi; BUG_ON(disk == NULL);
@@ -420,6 +421,9 @@ int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template) } else bi->name = bi_unsupported_name; + bdi = &disk->queue->backing_dev_info; + bdi->capabilities |= BDI_CAP_STABLE_WRITES; + return 0; } EXPORT_SYMBOL(blk_integrity_register);
@@ -434,10 +438,14 @@ EXPORT_SYMBOL(blk_integrity_register); void blk_integrity_unregister(struct gendisk *disk) { struct blk_integrity *bi; + struct backing_dev_info *bdi; if (!disk || !disk->integrity) return; + bdi = &disk->queue->backing_dev_info; + bdi->capabilities &= ~BDI_CAP_STABLE_WRITES; + bi = disk->integrity; kobject_uevent(&bi->kobj, KOBJ_REMOVE);
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 2a9a9ab..b82a8bb 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h@@ -253,6 +253,7 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); #define BDI_CAP_EXEC_MAP 0x00000040 #define BDI_CAP_NO_ACCT_WB 0x00000080 #define BDI_CAP_SWAP_BACKED 0x00000100 +#define BDI_CAP_STABLE_WRITES 0x00000200 #define BDI_CAP_VMFLAGS \ (BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP)
@@ -307,6 +308,11 @@ long wait_iff_congested(struct zone *zone, int sync, long timeout); int pdflush_proc_obsolete(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); +static inline bool bdi_cap_stable_writes(struct backing_dev_info *bdi) +{ + return bdi->capabilities & BDI_CAP_STABLE_WRITES; +} + static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi) { return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index d3ca2b3..a2f4c08 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c@@ -221,12 +221,23 @@ static ssize_t max_ratio_store(struct device *dev, } BDI_SHOW(max_ratio, bdi->max_ratio) +static ssize_t stable_page_writes_show(struct device *dev, + struct device_attribute *attr, char *page) +{ + struct backing_dev_info *bdi = dev_get_drvdata(dev); + + return snprintf(page, PAGE_SIZE-1, "%d\n", + bdi->capabilities & BDI_CAP_STABLE_WRITES ? 1 : 0); +} + #define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store) +#define __ATTR_RO(attr) __ATTR(attr, 0444, attr##_show, NULL) static struct device_attribute bdi_dev_attrs[] = { __ATTR_RW(read_ahead_kb), __ATTR_RW(min_ratio), __ATTR_RW(max_ratio), + __ATTR_RO(stable_page_writes), __ATTR_NULL, };